JP2003231743A - Polyester resin composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin composition improved in properties such as mechanical strengths, hardness, rigidity and gas barrier properties. <P>SOLUTION: A method is provided for producing a polyester resin composition comprising a polyester resin and 0.1-10 pts.wt. per 100 pts.wt. polyester resin, hydrotalcite, which includes adding the hydrotalcite to the polyester resin in an arbitrary stage before completion of polycondensation of the polyester resin and bringing the polycondensation to completion and a polyester resin composition produced thereby. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to mechanical strength, hardness,
The present invention relates to a polyester resin composition having improved rigidity, gas barrier property and the like.

[0002]

2. Description of the Related Art Polyethylene terephthalate and polybutylene terephthalate, which are typical polyesters, have excellent mechanical strength, heat resistance, hygiene, etc.
Used in the fields of bottles and molding materials. In order to meet the demand for advanced polyesters, fillers and resins have been combined to provide various functions. For example, weather resistance, flame retardancy, antistatic property, colorability,
It is blended with a filler to improve functions such as slidability, surface characteristics, antibacterial property, crystallinity, transparency, impact resistance, blocking resistance, conductivity, and gas barrier property.

In recent years, a nylon / clay (such as montmorillonite) hybrid utilizing intercalation has been extensively studied and put into practical use as a nanocomposite in automobile parts and the like. With this nanocomposite, even if the filling rate of the filler is only a few percent, high elastic modulus,
Effects such as improvement of heat resistance or improvement of gas barrier property are obtained. Examples of the filler used in this nanocomposite include swellable layered particles such as montmorillonite, smectite, and hectorite.

Hydrotalcite is known as such a layered inorganic particle. Hydrotalcite is a layered particle having an anion between layers and is used as a heat stabilizer for polyvinyl chloride. Also, in order to have a heat storage effect, it is added to an olefin film to be used as an agricultural film,
It is also used in pharmaceutical antacids because it dissolves in acid and has a pH control function. Further, WO01 / 42335 discloses the use of hydrotalcite as a polymerization catalyst for polyester.

For polyester resins, a composite system with layered inorganic particles has been investigated, but polyester resins such as polyethylene terephthalate have not been obtained which have satisfactory characteristics.

[0006]

An object of the present invention is to provide a polyester resin composition having improved mechanical strength, hardness, rigidity, gas barrier property, etc. in a composite system of a polyester resin and layered inorganic particles. Is.

[0007]

Means for Solving the Problems As a result of diligent studies on the combination of a polyester resin and inorganic fine particles, the present inventors have found that
The present invention has been reached. That is, the present invention is the following polyester resin composition and a method for producing the same.

(1) In a composition comprising a polyester resin and 0.1 to 10 parts by weight of hydrotalcite with respect to 100 parts by weight of the polyester resin, hydrotalcite may be optionally used until polycondensation of the polyester resin is completed. A method for producing a polyester resin composition, characterized in that polycondensation is completed after compounding in stages.

(2) A polyester resin composition produced by the method described in (1).

BEST MODE FOR CARRYING OUT THE INVENTION Hydrotalc used in the present invention
The general formula is [M²⁺ _1-xM³⁺ _x(OH)₂] [A^n- _{x / n}・ Z
H₂O] is a layered compound represented by a divalent metal (M²⁺)But
Trivalent metal (M ³⁺) Replaces the layer
Charged with laths and anions (A^n-) Exists between layers
To form. Divalent metals include magnesium and nickel
Aluminum, iron, trivalent metals such as zinc and zinc,
Chrome can be mentioned. Besides divalent and trivalent metals,
A monovalent metal such as aluminum or a tetravalent metal such as titanium may be included.

The method for producing the hydrotalcite used in the present invention is not particularly limited. For example, S. Miyata, Clays
The method described in Clay Miner., Vol. 28, page 50 (issued in 1980) is simple and preferable.

The hydrotalcite may be fired in the range of 300 to 800 ° C.

The resin composition of the present invention is mixed with hydrotalcite at any stage until the polycondensation is completed, and then the polycondensation is completed. In order to sufficiently disperse the hydrotalcite and remove the layer, it is desirable to add the hydrotalcite before the esterification reaction or the transesterification reaction.

It is further desirable that the hydrotalcite be dispersed in glycol in advance. Ethylene glycol and diethylene glycol are preferable as the glycol used for dispersion. It is considered that ethylene glycol and diethylene glycol are replaced with water existing between the hydrotalcite layers during heating during polyester polymerization.

It is considered that the object of the present invention can be achieved because hydrotalcite is efficiently dispersed in a polyester resin to promote layer peeling, thereby enabling molecular reinforcement in a nanometer size.

In order to disperse hydrotalcite efficiently in the polyester resin and promote delamination, it is desirable to use a dibasic acid intercalated between the hydrotalcite layers in advance. As a method for obtaining hydrotalcite in which a dibasic acid is intercalated, a method of using a dibasic acid as an anion source when synthesizing hydrotalcite, an anion of a hydrotalcite obtained in advance as a dibasic acid anion is used. Exchange method, using dibasic acid as an anion source when converting to hydrotalcite of the original structure by adding water to hydrotalcite from which interlayer anions have been eliminated by baking in the range of 300 to 800 ° C There are ways.

The surface area of hydrotalcite is 5 to 200
It is preferably m ² / g. If the surface area is less than 5 m ² / g, the transparency of the resin itself may decrease. Again 200
If it exceeds m ² / g, the melt viscosity at the time of polymerization will rapidly increase, and it may not be possible to obtain a resin having a desired molecular weight.

Hydrotalcite is a polyester resin 1
0.1 to 10 parts is blended with respect to 00 parts by weight. If it exceeds 10 parts by weight, the melt viscosity becomes too high, and it becomes difficult to increase the molecular weight of the polyester resin, and the obtained composition may be extremely brittle. On the other hand, if it is 0.1 part or less, the effect of adding hydrotalcite may be reduced.

Examples of the dibasic acid component of the polyester resin used in the present invention include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, and other aromatic dibasic acids, and amber. Acid, adipic acid, azelaic acid,
Aliphatic dibasic acids such as sebacic acid, dimer acid and cyclohexanedicarboxylic acid can be mentioned. As glycol components, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-
Butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, 3-methyl-
1,5-pentanediol, neopentyl glycol,
2-ethyl-2-butyl-1,3-propanediol,
Examples thereof include diethylene glycol, 1,4-cyclohexanedimethanol, an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, or a polyether glycol such as polyethylene glycol, polypropylene glycol or polytetramethylene glycol. Furthermore, lactones such as ε-caprolactone and δ-valerolactone, and oxycarboxylic acids such as p-hydroxyethoxybenzoic acid can also be used as raw materials for the polyester resin. Further, trifunctional or higher functional components such as trimethylolpropane, pentaerythritol, and trimellitic anhydride may be used together.

In order to improve the dispersibility of hydrotalcite and the layer peeling property, it is preferable to introduce a metal sulfonate group into the polyester resin. As a raw material for introducing the sulfonic acid metal salt into the polyester resin, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, sodium sulfoterephthalic acid, 2-sodiumsulfo-1,4-butanediol, 2,5 Examples include dicarboxylic acids such as dimethyl-3-sodium sulfo-2,5-hexanediol and glycols, and 5-sodium sulfoisophthalic acid and 5-potassium sulfoisophthalic acid are particularly preferable.

For the production of the polyester resin, a usual polymerization recipe for high molecular weight polyester can be used. That is, under conditions of excess glycol, after esterification reaction of dibasic acid and glycol, or after transesterification reaction of the methyl ester compound of dibasic acid and glycol,
Examples thereof include a melt polymerization method in which deglycolization is performed under high temperature and high vacuum in the presence of a metal catalyst such as antimony, titanium and germanium, and a solid phase polymerization method in which polymerization is performed in high vacuum below the melting point of the resin.

[0021]

The present invention will be specifically illustrated by the following examples. In the examples, "parts" means "parts by weight". Reduced viscosity is phenol / tetrachloroethane (6/4 weight ratio)
Was used as a solvent, and the concentration was measured at 30 ° C. at a concentration of 0.4 g / dl. The glass transition temperature is 20 ° C by a differential scanning calorimeter.
It was measured in minutes.

Example 1 163 parts of isophthalic acid, 5.9 parts of dimethyl 5-sodiumsulfoisophthalate, and 3-methyl-1,5-pentanediol were placed in a reaction vessel equipped with a thermometer, a stirrer, and a distilling cooling pipe. 255 parts of a solution in which hydrotalcite represented by Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O was dispersed at a ratio of 100: 2, 0.068 parts of tetrabutyl titanate as a reaction catalyst were charged, and the mixture was heated to 220 ° C. The temperature was raised. After the water was distilled off by the esterification reaction, the esterification reaction was completed while the temperature was raised to 240 ° C. Then, the pressure in the system was gradually reduced to finally reach 0.1 mmHg. The temperature at that time was kept at 260 ° C. Thus, a polyester resin composition containing 2% by weight of hydrotalcite was obtained. The composition of the polyester was analyzed by ¹ H-NMR. The obtained composition was dissolved in phenol / tetrachloroethane (6/4 weight ratio), and the reduced viscosity was measured. Further, the obtained composition was dissolved in methyl ethyl ketone / toluene (= 1/1 weight ratio), applied on a biaxially oriented polypropylene film and dried, and peeled off from the propylene film to obtain a coating film of the resin composition itself. It was The strength and elongation of the coating film, the storage elastic modulus in the glass state, and the water vapor barrier property were measured. Further, the polyester resin composition obtained for examining the degree of dispersion of hydrotalcite was added to methyl ethyl ketone / toluene (= 1/1 weight ratio) to obtain a solid content concentration of 1
Dissolve at 0% and observe the solution stability after 1 week storage at room temperature,
The case where the hydrotalcite did not settle was evaluated as ◯, and the case where the hydrotalcite settled was evaluated as x. The results are shown in Table 1.

Examples 2 and 3 As in Example 1, except that the concentration of the 3-methyl-1,5-pentanediol / hydrotalcite dispersion was changed to give different polyester compositions having different hydrotalcite contents. Got Evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

Example 4 As in Example 1, but without the use of 5.9 parts of dimethyl 5-sodium sulfoisophthalate, isophthalic acid and 3
A polyester resin composition was obtained from the -methyl-1,5-pentanediol / hydrotalcite dispersion. Evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

Examples 5 and 6 In Example 5, as in Example 1, except that the hydrotalcite used in Example 1 was added to ethylene glycol at 6.3%.
40 parts of what was dispersed in 3 parts, 165 parts of 3-methyl-1,5-pentanediol and 166 parts of isophthalic acid were reacted. Example 6 is similar to Example 1, except that Example 1
62 parts of the hydrotalcite used in 4) dispersed in diethylene glycol in 4%, 165 parts of 3-methyl-1,5-pentanediol and 166 parts of isophthalic acid were reacted. Evaluation was performed in the same manner as in Example 1. Table 1 shows the evaluation results
Shown in.

Comparative Examples 1 and 2 Examples 1 and 4 without using hydrotalcite
A polyester resin having a composition similar to that of was obtained. Evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 3 Hydrotalcite was mixed with the polyester resin solution of Comparative Example 1 (solvent: methyl ethyl ketone / toluene = 1/1 weight ratio) at a solid ratio of 100: 2, and glass beads were added to the paint shaker. And shake-dispersed for 6 hours. A dried coating film was obtained from this dispersion in the same manner as in Example 1.
Evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Examples 4 and 5 As in Example 1, except that the concentration of the 3-methyl-1,5-pentanediol / hydrotalcite dispersion was changed to obtain different polyester compositions having different hydrotalcite contents. Got In Comparative Examples 4 and 5, the content of hydrotalcite is outside the range of the present invention. Evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. In Comparative Example 5, the coating film obtained was very brittle, and the 50% modulus and water vapor barrier property could not be measured.

[0029]

[Table 1]

Examples 7, 8, 9 Inorganic Chemistry, vol 27, 462, published in 1988
Hydrotalcite (Mg ₄ Al ₂ (OH) ₁₂ (TA) .4H ₂ O) (TA: intercalated terephthalate anion synthesized by the method described on page 8)
Terephthalate ion) 10 parts ethylene glycol 90
Dispersed in parts. 166 terephthalic acid was placed in a reaction vessel equipped with the thermometer, the stirrer, and the distilling cooling pipe used in Example 1.
Part, 18.9 parts of ethylene glycol in which the above hydrotalcite is dispersed (1.9 parts of hydrotalcite,
Ethylene glycol 17 parts), ethylene glycol 10
Seven parts were charged and the esterification reaction was carried out under pressure. During that time, the temperature reached 230 ° C. 0.07 parts of tetrabutyl titanate was charged as a polycondensation reaction catalyst, and then the pressure in the system was gradually reduced to finally reach 0.1 mmHg.
The temperature at that time was kept at 270 ° C. Thus, a highly viscous polyethylene terephthalate (PET) composition containing 1% hydrotalcite was obtained.

The composition obtained was dissolved in phenol / tetrachloroethane and the reduced viscosity was measured. In addition, hot pressing method (a method of heating the resin to its melting point or softening point or higher to melt the resin, stretching it under pressure, and then rapidly cooling it with water)
The oxygen barrier property of the film obtained by JIS K 7
It was measured according to 126. Further, the oxygen barrier property of the film obtained by the same method was measured using PET containing no hydrotalcite. The oxygen barrier effect of hydrotalcite is shown in Table 2 as a reduction ratio of oxygen permeation amount due to the inclusion of hydrotalcite. In Example 8, the hydrotalcite used in Example 7 was dispersed in 1,3-propanediol, and polytrimethylene terephthalate (PTT) in which hydrotalcite was dispersed was obtained by the same polymerization method. In Example 9, polytetramethylene terephthalate (PBT) in which hydrotalcite was dispersed was obtained in the same manner as in Example 8. Table 2 shows the reduced viscosities and oxygen barrier properties of each.

[0032]

[Table 2]

As is clear from Tables 1 and 2, Example 1 in which hydrotalcite was added during the polycondensation of polyester
Nos. 9 to 9 are Comparative Examples 1 and 2 not containing hydrotalcite, Comparative Example 3 which was simply blended after polycondensation was completed, and Comparative Examples 4 and 5 whose hydrotalcite content was outside the scope of claims. In comparison, it can be seen that the strength, elastic modulus, and gas barrier property are dramatically improved.

[0034]

According to the present invention, mechanical strength, hardness, rigidity,
It is possible to obtain a polyester resin composition having improved gas barrier properties and the like. The polyethylene terephthalate film coated with this composition has improved gas barrier properties and can be used as a packaging material. Further, when blended with a curing agent, the rigidity is increased, and thus an adhesive having excellent adhesiveness can be obtained. Further, when it is mixed with a curing agent and applied to a steel sheet, a coated steel sheet excellent in scratches and the like can be obtained due to increased hardness.

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Claims (2)

[Claims] 1. A composition comprising a polyester resin and 0.1 to 10 parts by weight of hydrotalcite with respect to 100 parts by weight of the polyester resin, and any step until completion of polycondensation of the polyester resin with hydrotalcite. A method for producing a polyester resin composition, which comprises: 2. A polyester resin composition produced by the method according to claim 1.